Wave-signaling system



Sept- 28,1926. 1 60 \4 I Q. BUCHHOLZ WAVE smmmue SYSTEM Filed August 26. 1921 v2 sheets-she s; 1

INVENTOR JQMJW wam'w ATTORNEYS O. BUCH'IQ I QLZ 'WAVE smuALfN'G SYSTEM il August 26, 1921 2 Sheets-Sheet 2 F7 E. II g i g V /0 ac. 1 m 1- 5" 3 ,3 a I Z 0 Audlb-fi'cql/ency 3 Amplifier I l7 1? 6 TL20 76 l BY 7 l ATTORNEY Patented Sept. 28, 1926.

UNIEEE) STATES PATENT orFicE.

OTTO BUCI-IHOLZ, OF NIEDER-SCHONI-IAUSEN, NEAR BERLIN, GERMANY, ASSIGNOR TO "WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

Application filed August 26, 1921, Serial No. 495,698, and in Germany February 13, 19550.

The invention relates to a switch-arrange ment for producing oscillations by means of discharge-vessels, in which two or more are connected in cascade. The connection can be used for transmitting undamped oscillatio-ns in wireless telegraphy and telephony, or along wires, as well as, and this with especial advantage, for producing a local wave, which is brought into interference with an incoming wave.

The invention consists mainly therein, that an oscillating circuit is connected with the grid-circuit of the first discharge-vessel, while the connection between the first and second, or between two later tubes is Fig. 5 illustrates a still further modification.

One mode of practicing the invention is illustrated by the Fig. 1 in which a, b, 0 are three discharge-vessels, which are connected in cascade in known manner. (Z is a heating-battery, e a source of energy for the anode-circuit, f, g are resistances, over which the anodes of the tubes a, b, are connected to the source of energy, it are series-resistances for the cathodes. The connection between the anode of the first tube and the auxiliary electrode of the second tube and likewise the connection of the second tube with the controlling elecrode of the third is effected in a known manner over condensers 7c. The connection shown by the example is intended for heterodyne reception. A loop antenna '5 is consequently connected between the control electrode and the cathode of the first tube.

parallel to which an adjustable condenser Z is located.

The loop and the condenser represent, therefore, in themselves a closed oscillating circuit capable of being tuned. The con 5 nection between the second and third tubes of the cascade is preferably grounded at n over a switch or cutout 777/ of any desired construction and the connection between the previous pair of tubes is likewise grounded, over a high ohmic resistance 0. The telephone Q is located in the output circuit of the last tube being connected in parallel with a condenser p.

In order to use this system for reception of oscillations, the antenna is first tuned to the frequency of the oscillations which are to be received by closing theswitch m and tuning the antenna until a beat note of audible frequency is heard. The antenna may then be detuned with respect to the incoming wave and tuned to the frequency ofv the local oscillations.

Experience has shown that, in the entire connection a natural oscillation of the frequency of the antenna formation will appear and produce a surging sound in the telephone. If the ground connection at m is interrupted, this sound disappears and the connection has the effect of a pure cascade receiving connection, without hetero dyriingp The natural oscillations produced are absolutely constant. The invention can as well be used for producing a natural oscillation for heterodyning reception, as well as for sending 'of a wave. For the latter, it is only necessary that a periodic or aperiodic antenna formation be connected into the energy-circuit of the last tube. This is shown at 10 in Fig. 2. The oscillating circuit at the entrance of the first tube can in this case be formed by an ordinary self induction 11 and a tuning condenser 12. Experience has also proved that ordinary self induction coils may be employed in the input circuit instead of an antenna for use as a receiver.

irrounding the connection of the first pair of tubes over a high ohmic resistance is not always necessary. In most cases it is sufli- 10O cient'to ground the connection of one pair of tubes only, to obtain undisturbed and clear reception or to send out waves of suflicient range. This is indicated by omitting 0 in Figs. 2 to 5. Any other form of antenna, such as an elevated antenna connected to ground, as shown at 13 in Fig. 3, may be provided in place of the oscillating circuit comprising a solenoid and a tuning condenser at the entrance of the first tube. The connection between this antenna formation and the set of tubes in cascade may be eii'ected in any suitable manner.

Particularly an intermediate circuit 14imay be provided which may be tuned in any desired way. It can be tuned to the local frequency or to the incoming frequency or to the beat frequency. In the case of the intern'iediate connection it is, of course, also possible to tune the antenna to the incoming frequency and the intermediate circuit to the local frequency. Intermediate circuits as shown at 15, in Fig. i, can, of course, be provided between the single tubes and the telephone circuit and can be tuned to the incoming frequency, the local frequency or the beat frequency. The strength of the local oscillation can be controlled by varying the resistance of the ground connection; also by increasing or diminishing the number of tubes employed. It is of no consequence whether these tubes are incandescent or coated cathodes, as any kind of auxiliary tubes may be used for the purposes of the invention.

The application of the invention to an audio-frequency transformer, just described, contemplates not only the provision of an additional amplifying tube, indicated at 16 in Fig. 5, but also a telephone alone. In the latter case, a second transformer 17 may be used to connect the telephone to the last tube of the reception system and one pole of the telephone is grounded as shown at 18.

In either case there is likely to be interaction between the circuits of the telephone and those of the generator, causing the tele phone to sing.

In order to overcome these difficulties, an intermediate transformer 19 is placed in front of the audio-frequency amplifier, the secondary side of which is connected with the ground as shown at 20.

The receiving circuit is, furthermore, not grounded directly, but indirectly over a very small capacity 21. This way of grounding does not disturb the production of oscillations and effects a complete protection against singing.

I claim:

1. A vacuum tube oscillation generating system comprising a plurality of vacuum tubes each of which comprises a plate, filament and grid, said tubes being connected in cascade, an oscillating circuit associated with the grid of the first tube, an output circuit associated with the plate of the last tube, a ground connection to the grid of one of the tubes succeeding the first tube and means for connecting said ground connection to the grid of an adjacent tube, said means being insulated from the rest of the system.

1 vacuui'n tube oscillation generating system comprising a plurality of vacuum tubes each of which comprises a plate, filament and grid, said tubes being connected in cascade, an oscillating circuit associated with the grid of the first tube, an output circuit associated with the plate of the last tube, a ground connection to the grid of one of the tubes succeeding the first tube, a condenser in the circuit of the grid which is grounded to prevent grounding of the other tube elements, and means in the ground connection for controlling the oscillations of the system. 7

In testimony whereof I aiiix'my signature.

OTTO BUCHHOLZ. 

